US4437009A - Scanning electron microscope or similar equipment - Google Patents

Scanning electron microscope or similar equipment Download PDF

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Publication number
US4437009A
US4437009A US06/347,863 US34786382A US4437009A US 4437009 A US4437009 A US 4437009A US 34786382 A US34786382 A US 34786382A US 4437009 A US4437009 A US 4437009A
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Prior art keywords
specimen
opening
scanning electron
electron microscope
objective lens
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US06/347,863
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English (en)
Inventor
Shigetomo Yamazaki
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ABT NO 19-18 1-CHOME NAKACHO MUSASHINO-SHI TOKYO JAPAN A JAPANESE CORP KK
Topcon Corp
Akashi Seisakusho KK
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Akashi Seisakusho KK
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Assigned to KABUSHIKI KAISHA AKASHI SEISAKUSHO, A COMPANY OF JAPAN reassignment KABUSHIKI KAISHA AKASHI SEISAKUSHO, A COMPANY OF JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: YAMAZAKI, SHIGETOMO
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Assigned to KABUSHIKI KAISHA ABT, NO. 19-18, 1-CHOME, NAKACHO, MUSASHINO-SHI, TOKYO, JAPAN A JAPANESE CORP. reassignment KABUSHIKI KAISHA ABT, NO. 19-18, 1-CHOME, NAKACHO, MUSASHINO-SHI, TOKYO, JAPAN A JAPANESE CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KABUSHIKI KAISHA AKASHI, SEISAKUSHO, A JAPANES CORP.
Assigned to KABUSHIKI KAISHA TOPCON A CORP. OF JAPAN reassignment KABUSHIKI KAISHA TOPCON A CORP. OF JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KABUSHIKI KAISHA ABT A CORP. OF JAPAN
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
    • H01J37/28—Electron or ion microscopes; Electron or ion diffraction tubes with scanning beams

Definitions

  • This invention relates to a scanning electron microscope or similar equipment, and more particularly to a scanning electron microscope or similar equipment provided with a magnetic pole piece to decrease the magnetic flux leaked through an opening of a lower pole of an electromagnetic objective lens.
  • a conventional scanning electron microscope is accompanied by a drawback that, as shown in FIG. 1, its resolution is limited to an order of 60-70 ⁇ or so because it is designed to place a specimen c below the lower pole b of an electromagnetic objective lens a and it thus has a long focal distance and a large aberration coefficient.
  • the diameter of the opening of the lower pole b has to be great to permit a disposition of the specimen c at a point above the lower pole b. Accordingly, when the specimen c is placed below the lower pole b, more magnetic flux tends to leak through the thus-enlarged opening of the lower pole b, thereby deleteriously affecting the collection of secondary electrons and magnetizing the magnetic specimen, and, corollary to this, lowering the S/N ratio(signal-to-noise ratio) and consequently deteriorating the quality of an image to be obtained.
  • letters d, e and f designate a detector, amplifier and cathode-ray tube respectively.
  • the present invention contemplates to solve the above-described drawbacks or problems of the prior art scanning electron microscopes and similar equipments.
  • the object of this invention is to provide a scanning electron microscope or similar equipment which can always provide a specimen image of good quality regardless of the location of the specimen so as to make itself applicable for varied purposes.
  • the present invention provides in one aspect a scanning electron microscope or similar equipment, which comprises an electromagnetic objective lens having its lens center between the upper and lower poles thereof, an opening formed on said lower pole so that a specimen may be passed through the opening and placed in the vicinity of the lens center, and a magnetic pole piece defining an aperture having a diameter smaller than that of the opening and detachably provided in the opening so as to decrease the magnetic flux leaked through the opening when the specimen is placed below the lower pole.
  • the above scanning electron microscope or similar equipment further comprises a change-over system for varying the crossing point between a scanning charged particle beam and an optical axis depending whether the specimen is placed in the vicinity of the lens center or below the lower pole.
  • a specimen can be placed either below the lower pole of the objective lens or in the vicinity of the lens center of the objective lens as the operator desires, thereby making the scanning electron microscope or similar equipment applicable for varied purposes.
  • FIG. 1 is a schematic illustration of both electron beam focusing system and detection system in a conventional scanning electron microscope
  • FIG. 2 illustrates schematically a scanning electron microscope according to one embodiment of this invention, in which a specimen is placed below the lower pole of the objective lens thereof;
  • FIG. 3 is similar to FIG. 2 but the specimen is placed in the vicinity of the lens center of the objective lens;
  • FIG. 4 is a block diagram of a crossing point change-over system adopted in the scanning electron microscope shown in FIGS. 2 and 3;
  • FIGS. 5 and 6 are each a schematic illustration showing the crossing point between the scanning beam and optical axis.
  • the scanning electron microscope has an electromagnetic objective lens 1 disposed at a lower position in a microscope column.
  • This objective lens 1 is constructed as a lens having its lens center G between its upper pole 2 and lower pole 3.
  • the lower pole 3 of the objective lens 1 defines an opening 3a adapted to pass a specimen 4 and a specimen stage therethrough, whereby permitting to place the specimen 4 in the vicinity of the lens center G.
  • the diameter D UN of the opening in the lower pole 3 is generally 15 mm or greater in commercially available scanning electron microscopes.
  • the upper pole 2 also defines an opening therethrough.
  • Its diameter D UP is also 15 mm or greater in commercially available scanning electron microscopes.
  • the diameter D UP ranges for example from 20 to 30 mm.
  • the ratio of the diameters D UP to D UN namely, D UP /D UN generally ranges from 0.6 to 1.6.
  • the scanning electron microscope is also provided with a magnetic pole piece 5, which can be screwed up in the opening 3a of the lower pole 3.
  • This magnetic pole piece 5 defines a small aperture 5a, the diameter of which is smaller than the diameter of the opening 3a.
  • the diameter D S of the small aperture 5a is generally of the order of 10 mm or so in commercially available scanning electron microscopes.
  • a crossing point change-over system C is connected with a deflection member so as to change over the crossing point of the scanning beam and optical axis, as shown in FIGS. 5 and 6, depending whether the specimen 4 is placed below the lower pole 3 of the objective lens 1 or in the vicinity of the lens center G of the objective lens 1.
  • the crossing point change-over system C is constituted, as shown in FIG. 4, by a first and second power supplies 6, 7 adapted to output D.C. electric signals of different values respectively and a change-over switch 8 for feeding either one of the electric signals from the power supplies 6, 7 to a deflection member (not illustrated) in accordance with the location of the specimen 4.
  • the change-over switch 8 is turned to a terminal a (see FIG. 4) and the signal from the first power supply 6 is fed to the unillustrated deflection member.
  • the deflection member is then actuated with a deflection angle ratio ( ⁇ / ⁇ ) which is determined by the signal from the first power supply 6.
  • the change-over switch 8 is turned to a terminal b (see FIG. 4) and the signal from the second power supply 7 is fed to the above-described deflection member.
  • the deflection member is then actuated with another deflection angle ratio [ ⁇ / ⁇ '( ⁇ / ⁇ )] which is determined by the signal from the second power supply 7.
  • the crossing point between the scanning beam B and optical axis A is moved to a forward focal point F of the objective lens 1 under the influence of a forward magnetic field of the specimen, thereby making the angle ⁇ of the incident beam to the specimen 4 be substnatially a right angle.
  • one or more lower detectors 9 are provided below the lower pole 3 of the objective lens 1.
  • one or more upper detectors 10 are disposed above the objective lens 1. These detectors 9, 10 are connected to a common adder 13 through their respective amplifiers 11, 13. The adder 13 is in turn connected to a cathode-ray tube 15 via an amplifier 14.
  • the specimen 4 is scanned two-dimensionally by an electron beam in a manner known per se in the art. Secondary electrons and the like particles given off from the specimen 4 are then detected by the lower detector 9 principally. Then, the cathode-ray tube 15 is subjected to intensity modulation by virtue of a signal from the detector 9, thereby displaying an image of the specimen 4 on the screen of the cathode-ray tube 15 for observation.
  • the thus-obtained image is of good quality since the scanning beam B intersects with the optical axis A at the lens center G of the objective lens 1 and, in addition, the leakage of magnetic flux is considerably decreased by the magnetic pole piece 5.
  • the specimen 4 When the specimen 4 is placed in the vicinity of the lens center G of the objective lens 1 to observe its image, it is required to detach the magnetic pole piece 5 from the lower pole 3, to insert the specimen 4 to a point near the lens center G of the objective lens 1 through the opening 3a of the lower lens 3 of the objective lens 1, and then to turn, either automatically or manually, the change-over switch 8 to the terminal b.
  • the specimen 4 is scanned two-dimensionally by an electron beam in a manner known per se in the art. Secondary electrons and the like particles given off from the specimen 4 are mainly detected by the upper detector 10. Then, the cathode-ray tube 15 is subjected to intensity modulation by a detection signal from the detector 10, thereby displaying an image of the specimen 4 on the screen of the cathode-ray tube 15 for observation. Owing to the above-described arrangement, the resolution has been improved from the order of 70 ⁇ to the order of 30 ⁇ and, in addition, the quality of images has also been improved because the scanning beam B and optical axis A intersect at the forward focal point F.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Sources, Ion Sources (AREA)
US06/347,863 1981-03-03 1982-02-11 Scanning electron microscope or similar equipment Expired - Lifetime US4437009A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP56-30266 1981-03-03
JP56030266A JPS57145259A (en) 1981-03-03 1981-03-03 Scanning type electron microscope and its similar device

Publications (1)

Publication Number Publication Date
US4437009A true US4437009A (en) 1984-03-13

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US06/347,863 Expired - Lifetime US4437009A (en) 1981-03-03 1982-02-11 Scanning electron microscope or similar equipment

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US (1) US4437009A (ja)
JP (1) JPS57145259A (ja)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4818874A (en) * 1987-04-17 1989-04-04 Jeol Ltd. Scanning electron microscope
EP0329097A2 (en) * 1988-02-16 1989-08-23 Fujitsu Limited Magnetic object lens of electron beam exposure apparatus
US4864228A (en) * 1985-03-15 1989-09-05 Fairchild Camera And Instrument Corporation Electron beam test probe for integrated circuit testing
US4912405A (en) * 1985-08-16 1990-03-27 Schlumberger Technology Corporation Magnetic lens and electron beam deflection system
US4916315A (en) * 1988-04-01 1990-04-10 Hitachi, Ltd. Scanning electron microscope for observing and measuring minute pattern of sample
WO1991003832A1 (en) * 1989-08-31 1991-03-21 Bell Communications Research, Inc. Electron microscope with an asymmetrical immersion lens
US5598002A (en) * 1993-08-26 1997-01-28 Hitachi, Ltd. Electron beam apparatus
US20030230714A1 (en) * 2002-05-15 2003-12-18 Akira Yonezawa Electron beam apparatus
US20120132803A1 (en) * 2009-08-10 2012-05-31 Hitachi High-Technologies Corporation Charged particle beam device and image display method
US8389962B2 (en) * 2011-05-31 2013-03-05 Applied Materials Israel, Ltd. System and method for compensating for magnetic noise

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5978434A (ja) * 1982-10-26 1984-05-07 Akashi Seisakusho Co Ltd 電磁式対物レンズ
JPS60155162U (ja) * 1984-03-26 1985-10-16 日本電子株式会社 走査電子顕微鏡用対物レンズ

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4851578A (ja) * 1971-10-29 1973-07-19
JPS5758689Y2 (ja) * 1977-02-08 1982-12-15
JPS54935A (en) * 1977-06-06 1979-01-06 Hitachi Ltd Pattern detector
JPS5532298U (ja) * 1978-08-24 1980-03-01
JPS5841642Y2 (ja) * 1979-01-08 1983-09-20 株式会社島津製作所 電子線照射分析装置の試料ホルダ−
JPS5914222B2 (ja) * 1979-02-28 1984-04-03 日本電子株式会社 走査電子顕微鏡等用倍率制御装置

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4864228A (en) * 1985-03-15 1989-09-05 Fairchild Camera And Instrument Corporation Electron beam test probe for integrated circuit testing
US4912405A (en) * 1985-08-16 1990-03-27 Schlumberger Technology Corporation Magnetic lens and electron beam deflection system
US4818874A (en) * 1987-04-17 1989-04-04 Jeol Ltd. Scanning electron microscope
EP0329097A2 (en) * 1988-02-16 1989-08-23 Fujitsu Limited Magnetic object lens of electron beam exposure apparatus
EP0329097A3 (en) * 1988-02-16 1990-06-27 Fujitsu Limited Magnetic object lens of electron beam exposure apparatus
US4916315A (en) * 1988-04-01 1990-04-10 Hitachi, Ltd. Scanning electron microscope for observing and measuring minute pattern of sample
WO1991003832A1 (en) * 1989-08-31 1991-03-21 Bell Communications Research, Inc. Electron microscope with an asymmetrical immersion lens
US5079428A (en) * 1989-08-31 1992-01-07 Bell Communications Research, Inc. Electron microscope with an asymmetrical immersion lens
US5598002A (en) * 1993-08-26 1997-01-28 Hitachi, Ltd. Electron beam apparatus
US20030230714A1 (en) * 2002-05-15 2003-12-18 Akira Yonezawa Electron beam apparatus
US6949745B2 (en) * 2002-05-15 2005-09-27 Sii Nanotechnology Inc. Electron beam apparatus
US20120132803A1 (en) * 2009-08-10 2012-05-31 Hitachi High-Technologies Corporation Charged particle beam device and image display method
US9202669B2 (en) 2009-08-10 2015-12-01 Hitachi High-Technologies Corporation Charged particle beam device and image display method for stereoscopic observation and stereoscopic display
US8389962B2 (en) * 2011-05-31 2013-03-05 Applied Materials Israel, Ltd. System and method for compensating for magnetic noise

Also Published As

Publication number Publication date
JPS57145259A (en) 1982-09-08
JPH036615B2 (ja) 1991-01-30

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